/Engine/Source/Runtime/UMG/Public/Blueprint/UserWidgetPool.h
Gets an instance of a widget of the given class. The underlying slate is stored automatically as well, so the returned widget is fully constructed and GetCachedWidget will return a validSWidget.
template<typename UserWidgetT> UserWidgetT * GetOrCreateInstance ( [TSubclassOf](API\Runtime\CoreUObject\Templates\TSubclassOf)< UserWidgetT > WidgetClass )